High resolution signals in patient monitoring and recording systems are used to detect and characterize small changes and distortion in patient signals, such as electrocardiogram (ECG), intra-cardiac electrogram (ICEG) and blood pressure signals, especially nonlinear, non-stationary and non-uniform changes and jittering within patient signals. Known medical signal conversion and acquisition systems typically employ linear and uniform analogue to digital conversion of patient signals for high resolution signal acquisition with continuous high sampling rate. However this high data acquisition rate may lead to over-sampling of signals and generate excessive amounts of data, and pose an additional processing burden in signal filtering, data compression and transmission. Additionally, in many medical signals from a patient (e.g. surface ECG signals, intra-cardiac electrograms), the portion of interest of the signal, such as a QRS complex is of higher frequency than remaining portions of the signal and may comprise a small portion (e.g. 15-30%) of the whole signal cycle.
Known systems use linear and uniform sampling and data acquisition. The data conversion usually involves sampling at 2-5 times the maximum frequency of the medical signals (according to the Nyquist-Shannon sampling theorem) to achieve adequate signal quality. The known sampling systems may cause over-sampling and redundant data acquisition and may fail to adequately sample fast activity wave portions and may over sample in relatively low frequency wave portions. Further, known medical recording and analysis systems based on linear data sampling and acquisition, offer limited sampling control and sensitivity particularly in the presence of noise and may distort derived signal frequency spectrum data. A system according to invention principles addresses these deficiencies and related problems.